This invention relates generally to plastic packaging bags which are releasably secured to one or more tapes in imbricated form. Specifically, the invention relates to side sealed taped bags having an extended lip rear panel.
Side sealed bags are conventionally made in series from layflat tubular film by slitting one edge of the collapsed layflat tubing and transversely heat sealing the tubing at regular intervals with pairs of juxtaposed heat seals while imparting a line of weakness between the pair of heat seals. The slit edge of the tubing forms the bag mouth while the transverse seals form the bag sides. In other words the pair of heat seals will form the right side of one bag and the left side of an adjacent bag. The line of weakness between the heat seals allows separation of the bags from each other. When making a series of extended lip bags, a longitudinal strip along one face of the layflat tubing is usually removed adjacent the tubing edge which is to be the mouth end of the bags. Such bags thus have a front panel that is shorter than their rear panel so that the bag mouth is at the upper edge of the shortened front bag panel. The bags may be secured to one or more tapes by adhereing the tape(s) to the external surface of the rear panel of the bags at one or more points per bag. The thus taped bags may be taped in imbricated form. Product loading utilizing taped bags typically includes the steps of providing a roll of taped bags at a product loading station and thereafter directing an air jet at the mouth end of the uppermost bag to inflate the bag. At this point a product is inserted into the inflated bag with sufficient force to release or tear the bag from the tape which generally maintains bag alignment. It is desired that tearing or releasing of the bags preferably occurs at the point(s) at which the bag is adhered to the tape(s). This sequence is repeated for a series of products until the roll of taped bags is exhausted.
A substantial problem encountered with side sealed taped bags involves side seal integrity during product loading. The termination points of the side seals at the mouth end of the bag are relatively weak so that, upon the thrusting of a product into an inflated taped bag, forces are imposed upon the bag mouth that tend to tear or delaminate the side seals at their relatively weak termination points before the bag is torn or released from the tape(s). It is noted that the foregoing problem does not appear when using end sealed taped bags or end sealed wicketed bags. With regard to side sealed wicketed bags, one approach taken in attempting to overcome this problem has been to provide tear initiating slits at the tops of the wicket holes. However, this approach has the disadvantage that snagging problems are caused when bags of this design are utilized in bag separating apparatus wherein a perforated series of such bags is separated into individual bags. Also the tear initiation slits do not preclude the possibility of the side seals failing at their termination points. The present invention is directed to integral reinforcement of the side seal terminations in side sealed taped bags through extension of the side seals and thus the side seal termination points. As is disclosed in application Ser. No. 06/540,212 filed on Oct. 7, 1983, this reinforcement concept has been applied to wicketed bags. The subject matter of U.S. application Ser. No. 06/540,212 is hereby incorporated by reference.
Of general interest is the disclosure of U.S. Pat. No. 3,372,857 for "Side Seal Bag Construction with Stress Relief Notch" issued Mar. 12, 1968 to Brayla, directed to a side sealed extended lip wicketed bag having heat fused stress relief notches near the mouth end side seal terminations to prevent side seal delamination during loading of a product into the bag while wicketed.
Of additional general interest in the disclosure of U.S. Pat. No. 3,804,322 for "Plastic Bag Having Arcuate Closed End and Arcuate Lipped Open End" issued Apr. 16, 1974 to Ericson, directed to end sealed wicketed bags having an arcuate mouth end and an arcuate cut out in the front bag panel opposite wicketing holes in the rear bag panel. The configuration forms marginal ears at the mouth end of the end sealed bag for manual gathering of the bag mouth following product loading.